Sum Index formula - glitch

I'm using the following formula to sum from a cell to the end of the columns.
For instance sum from cell C3 to the end of row 3.

SUM((C3:INDEX(3:3,MATCH(16384,3:3))))

It works except that if I have a dash "-" as the first entry, it seems to go backwards a cell.
In the table below, the yellow cells are incorrect, the sum should be zero.

The dash "-" is required instead of 0.


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